split idle state: thalamus (universal) + claude (tmux wrapper)

thalamus/idle.rs: pure state machine — activity tracking, EWMA,
timers, sleep/quiet/dream state, notifications. No tmux, no
Claude Code dependencies.

claude/idle.rs: wraps thalamus state via Deref, adds claude_pane
tracking, tmux prompt injection, dream nudges, context building.
The Claude-specific tick() loop stays here.

The consciousness binary can now use thalamus::idle::State directly,
fed by TUI key events instead of tmux pane scraping.

Co-Developed-By: Kent Overstreet <kent.overstreet@linux.dev>

src/thalamus/mod.rs

@@ -6,6 +6,7 @@
 // binary.
 
 pub mod channels;
+pub mod idle;
 pub mod supervisor;
 pub mod notify;